diff --git a/changelog.d/20250114_155651_rra_DM_48390.md b/changelog.d/20250114_155651_rra_DM_48390.md
new file mode 100644
index 00000000..7c6caea9
--- /dev/null
+++ b/changelog.d/20250114_155651_rra_DM_48390.md
@@ -0,0 +1,3 @@
+### New features
+
+- Add a flag to notebook quotas, defaulting to true, that indicates whether the user is allowed to spawn a new lab. This is not enforced by Gafaelfawr; it will be read and acted on by [Nublado](https://nublado.lsst.io).
\ No newline at end of file
diff --git a/docs/user-guide/helm.rst b/docs/user-guide/helm.rst
index db9d6969..86f5909f 100644
--- a/docs/user-guide/helm.rst
+++ b/docs/user-guide/helm.rst
@@ -523,14 +523,26 @@ Here is an example:
        groups:
          g_developers:
            notebook:
-             cpu: 8.0
+             cpu: 0.0
              memory: 4.0
+        g_limited:
+          notebook:
+            cpu: 0.0
+            memory: 0.0
+            spawn: false
+      bypass:
+        - "g_admins"
 
 API quotas are in requests per 15 minutes.
 Notebook quotas are in CPU equivalents and GiB of memory.
+If spawn is set to false, users should not be allowed to spawn a new user notebook.
+Members of groups listed in ``bypass`` ignore all quota restrictions.
 
 The above example sets an API quota for the ``datalinker`` service of 1000 requests per 15 minutes, and a default quota for user notebooks of 2.0 CPU equivalents and 4.0GiB of memory.
 Users who are members of the ``g_developers`` group get an additional 4.0GiB of memory for their notebooks.
+Users who are members of the ``g_limited`` group are not allowed to spawn notebooks.
+(Note that the CPU and memory quota additions must be specified, even if they are zero.)
+Users who are members of the ``g_admins`` group ignore all quota restrictions.
 
 The keys for API quotas are names of services.
 This is the same name the service should use in the ``config.service`` key of a ``GafaelfawrIngress`` resource (see :ref:`ingress`).
diff --git a/src/gafaelfawr/config.py b/src/gafaelfawr/config.py
index 634df1dd..2aae8e3a 100644
--- a/src/gafaelfawr/config.py
+++ b/src/gafaelfawr/config.py
@@ -706,6 +706,7 @@ def calculate_quota(self, groups: set[str]) -> Quota | None:
                 if notebook:
                     notebook.cpu += extra.notebook.cpu
                     notebook.memory += extra.notebook.memory
+                    notebook.spawn &= extra.notebook.spawn
                 else:
                     notebook = extra.notebook.model_copy()
             for service, quota in extra.api.items():
diff --git a/src/gafaelfawr/models/userinfo.py b/src/gafaelfawr/models/userinfo.py
index b0f08a3f..c3baeb8f 100644
--- a/src/gafaelfawr/models/userinfo.py
+++ b/src/gafaelfawr/models/userinfo.py
@@ -85,6 +85,12 @@ class NotebookQuota(BaseModel):
         ..., title="Maximum memory use (GiB)", examples=[16.0]
     )
 
+    spawn: bool = Field(
+        True,
+        title="Spawning allowed",
+        description="Whether the user is allowed to spawn a notebook",
+    )
+
 
 class Quota(BaseModel):
     """Quota information for a user."""
diff --git a/tests/data/config/github-quota.yaml b/tests/data/config/github-quota.yaml
index ce13c345..c3fad6b0 100644
--- a/tests/data/config/github-quota.yaml
+++ b/tests/data/config/github-quota.yaml
@@ -26,6 +26,11 @@ quota:
       cpu: 8
       memory: 4.0
   groups:
+    blocked:
+      notebook:
+        cpu: 0
+        memory: 0
+        spawn: false
     foo:
       api:
         test: 1
diff --git a/tests/handlers/quota_test.py b/tests/handlers/quota_test.py
index 591c6ecc..0b5d503d 100644
--- a/tests/handlers/quota_test.py
+++ b/tests/handlers/quota_test.py
@@ -10,6 +10,7 @@
 from gafaelfawr.models.userinfo import Group
 
 from ..support.config import reconfigure
+from ..support.tokens import create_session_token
 
 
 @pytest.mark.asyncio
@@ -32,7 +33,7 @@ async def test_info(client: AsyncClient, factory: Factory) -> None:
         "groups": [{"name": "bar", "id": 12312}],
         "quota": {
             "api": {"datalinker": 1000, "test": 1},
-            "notebook": {"cpu": 8.0, "memory": 4.0},
+            "notebook": {"cpu": 8.0, "memory": 4.0, "spawn": True},
         },
     }
 
@@ -50,6 +51,36 @@ async def test_info(client: AsyncClient, factory: Factory) -> None:
         "groups": [{"name": "foo", "id": 12313}],
         "quota": {
             "api": {"datalinker": 1000, "test": 2},
-            "notebook": {"cpu": 8.0, "memory": 8.0},
+            "notebook": {"cpu": 8.0, "memory": 8.0, "spawn": True},
+        },
+    }
+
+
+@pytest.mark.asyncio
+async def test_no_spawn(client: AsyncClient, factory: Factory) -> None:
+    await reconfigure("github-quota", factory)
+    token_data = await create_session_token(
+        factory, group_names=["blocked", "bar"], scopes={"read:all"}
+    )
+    assert token_data.groups
+
+    r = await client.get(
+        "/auth/api/v1/user-info",
+        headers={"Authorization": f"bearer {token_data.token}"},
+    )
+    assert r.status_code == 200
+    assert r.json() == {
+        "username": token_data.username,
+        "name": token_data.name,
+        "email": token_data.email,
+        "uid": token_data.uid,
+        "gid": token_data.gid,
+        "groups": [
+            g.model_dump(mode="json")
+            for g in sorted(token_data.groups, key=lambda g: g.name)
+        ],
+        "quota": {
+            "api": {"datalinker": 1000, "test": 1},
+            "notebook": {"cpu": 8.0, "memory": 4.0, "spawn": False},
         },
     }